Explanation:
A night sky can glow in fascinating ways.
Through a clearing in the woods, the
pictured sky above
Alaska
shines by reflected light from a nearby city,
by the brightness of the
Moon, and by
aurora.
The night sky in or near a city appears to contain
relatively few stars because lights there reflect off atmospheric particles,
hiding stars in a diffuse glow.
The bright Moon also creates a
diffuse sky glow, although much less bright than the analogous
blue-sky glow created during the day by the Sun.
Particles from the Sun crashing into the
Earth's atmosphere are seen here as bands of aurora.
These glows also illuminate visible
clouds.
Auroral displays are becoming more frequent as the Sun approaches
Solar Maximum.